The present invention relates to a magnetic head drum of a helical-scan type for magnetically recording and reading video data on magnetic tape.
Such a magnetic head drum known in the art comprises a stationary spindle, a stationary drum secured to the spindle, a rotary drum rotatably supported on the spindle, and a motor for rotating the rotary drum. The stationary drum includes a cylindrical side wall having a helical guide shoulder for helically guiding magnetic tape thereon on its outer circumferential face. The rotary drum includes a cylindrical side wall having at its outer periphery a magnetic head for recording and reading video signals on the magnetic tape. The motor comprises a rotor secured to the rotary drum, a stator securely connected to the spindle so as to be remote at a predetermined distance from the rotor, and a back yoke secured to a top end of the cylindrical side wall of the rotary drum. A transformer for the stator is secured to the stationary drum in opposed relationship to a transformer for the rotor which is secured to the rotary drum and electrically connected to the magnetic head. The stator is electrically connected to a flexible circuit board via a guide protector which extends radially and outwardly from a top end portion of the spindle above the rotary drum so that the flexible circuit board is remote from the back yoke mounted on the rotary drum. Further, the stator is provided with a damper member in order to restrain vibration of the stator upon rotation of the rotary drum around the spindle. The vibration causes a noise, viz, electromagnetic noise of the motor.
However, since the vibration of the stator upon rotation is not sufficiently restrained by the damper member, electromagnetic noise is still generated. Further, provision of the damper creates a drawback in that the total weight of the magnetic head drum is increased.
In addition, since the guide protector is projectingly arranged above the rotary drum, reduction in height and weight of the magnetic head drum is disturbed.
There is great demand for a magnetic head drum which is rotatable at high speed without generating electromagnetic noise and which has reduced size and weight.